1. Field of the Invention
The present invention relates to a heat recovery system utilizing a non-azeotropic mixture as the working fluid. More specifically, the present invention relates to a heat exchanger dealing with an evaporation or condensation of the non-azeotropic mixture.
2. Description of the Prior Art
A heat recovery system based upon a Rankine cycle which is adapted to recover heat from warm waste water discharged from a factory, and to utilize it for generating electric power or the like as the energy source has been well known. In such conventional system, a coolant such as a fluorine gas is used as the working fluid, which circulates through a working fluid system constituted by connecting an evaporator, steam turbine and condenser in a closed loop. The working fluid, which is initially a liquid, is heated in the evaporator and changed into vapor having a high temperature and pressure, which is then fed into the steam turbine to work while passing therethrough while expanding. The vapor reduced to a low temperature and pressure after completing the work is exhausted from the steam turbine to the condenser, in which it is cooled and condensed and pumped back into the evaporator to repeat similar cycles thereafter. An output shaft of the steam turbine is coupled to the load of a generator or the like.
In such a heat recovery system, since the larger the temperature difference the higher the efficiency, it is devised to increase the temperature of working fluid vapor supplied to the steam turbine by providing a heater at an outlet of the evaporator. In such case, however, an additional equipment must be specially installed, resulting in a high cost.